Wang Min, Lv Qingbo, Zhao Liding, Wang Yao, Luan Yi, Li Zhengwei, Fu Guosheng, Zhang Wenbin
Key Laboratory of Cardiovascular Intervention and Regenerative Medicine of Zhejiang, Department of Cardiology, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang 310027, P.R. China.
Exp Ther Med. 2020 Feb;19(2):871-882. doi: 10.3892/etm.2019.8312. Epub 2019 Dec 10.
Hyperglycemia caused by diabetes mellitus could increase the risk of diabetic cardiomyopathy. However, to the best of our knowledge, the underlying mechanism of this process is still not fully explored. Thus, developing ways to prevent hyperglycemia can be beneficial for diabetic patients. The present study was designed to investigate the influence of metoprolol and bisoprolol on the cardiomyocytic hypertrophy of neonatal rat cardiomyocytes. Cardiomyocytes were cultured in two types of media: One with low glucose levels and one with high glucose levels. Cardiomyocytes cultured in high glucose were further treated with the following: A protein kinase C (PKC) inhibitor, an NF-κB inhibitor, metoprolol or bisoprolol. The pulsatile frequency, cellular diameter and surface area of cardiomyocytes were measured. Protein content and [H]-leucine incorporation were determined, atrial natriuretic peptide (ANP), α-myosin heavy chain (α-MHC) and β-myosin heavy chain (β-MHC) mRNA levels were calculated by reverse transcription-quantitative PCR, while the expression and activation of PKC-α, PKC-β, NF-κB, tumor necrosis factor-α (TNF-α), and c-fos were detected by western blotting. Metoprolol or bisoprolol were also used in combination with PKC inhibitor or NF-κB inhibitor to determine whether the hypertrophic response would be attenuated to a lower extent compared with metroprolol or bisoprolol alone. Cardiomyocytes cultured in high glucose presented increased pulsatile frequency, cellular diameter, surface area, and protein content and synthesis, higher expression of ANP and β-MHC, and lower α-MHC expression. High glucose levels also upregulated the expression and activation of PKC-α, PKC-β, NF-κB, TNF-α and c-fos. Metoprolol and bisoprolol partly reversed the above changes, while combined use of metoprolol or bisoprolol with PKC inhibitor or NF-κB inhibitor further ameliorated the hypertrophic response mentioned above to lower levels compared with using metroprolol or bisoprolol alone. In conclusion, metoprolol and bisoprolol could prevent hypertrophy of cardiomyocytes cultured in high glucose by the inhibition of the total and phospho-PKC-α, which could further influence the PKC-α/NF-κB/c-fos signaling pathway.
糖尿病引起的高血糖会增加糖尿病性心肌病的风险。然而，据我们所知，这一过程的潜在机制仍未得到充分探索。因此，开发预防高血糖的方法可能对糖尿病患者有益。本研究旨在探讨美托洛尔和比索洛尔对新生大鼠心肌细胞肥大的影响。心肌细胞在两种培养基中培养：一种是低糖水平的培养基，另一种是高糖水平的培养基。在高糖环境中培养的心肌细胞进一步用以下物质处理：蛋白激酶C（PKC）抑制剂、核因子κB（NF-κB）抑制剂、美托洛尔或比索洛尔。测量心肌细胞的搏动频率、细胞直径和表面积。测定蛋白质含量和[H]-亮氨酸掺入量，通过逆转录定量聚合酶链反应计算心钠素（ANP）、α-肌球蛋白重链（α-MHC）和β-肌球蛋白重链（β-MHC）的信使核糖核酸水平，同时通过蛋白质印迹法检测PKC-α、PKC-β、NF-κB、肿瘤坏死因子-α（TNF-α）和c-fos的表达及激活情况。美托洛尔或比索洛尔还与PKC抑制剂或NF-κB抑制剂联合使用，以确定与单独使用美托洛尔或比索洛尔相比，肥大反应是否会在更低程度上减弱。在高糖环境中培养的心肌细胞表现出搏动频率增加、细胞直径增大、表面积增大、蛋白质含量和合成增加、ANP和β-MHC表达升高以及α-MHC表达降低。高糖水平还上调了PKC-α、PKC-β、NF-κB、TNF-α和c-fos的表达及激活。美托洛尔和比索洛尔部分逆转了上述变化，而美托洛尔或比索洛尔与PKC抑制剂或NF-κB抑制剂联合使用，与单独使用美托洛尔或比索洛尔相比，进一步将上述肥大反应改善到更低水平。总之，美托洛尔和比索洛尔可通过抑制总PKC-α和磷酸化PKC-α来预防在高糖环境中培养的心肌细胞肥大，这可能进一步影响PKC-α/NF-κB/c-fos信号通路。
